required viewing

"Required viewing" categorises video of any format that you expect another person to have seen before you can even begin to consider them worthy of your attention.
Most often used by geeks who will refuse to explain what they are talking about once they realise you've not seen the TV show or movie.
Can also be used for audio: "Required listening".

Any form of media that simply must be seen in order for you to be a proper member of a group.